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Description of problem:
I created 2 partitions (type 0xfd) and made a RAID1 out of them
(/dev/md0). 
Then I did pvcreate on /dev/md0, created a volume group, created a
logical 
volume and then created an ext3 filesystem on the lv. I added an entry 
to /etc/fstab so that the lv mounts automatically at boot.

After rebooting the system, "mount" shows that my lv has been mounted 
successfuly. I tried writing and reading to that filesystem and was 
successful. However, pvdisplay on /dev/md0 showed nothing so I did a
cat on /proc/mdstat. RAID wasn't active at all!!! I did raidstart
/dev/md0 and that's when /dev/md0 showed up in pvdisplay.

Could somebody please give an explanation to the this. How was I able
to mount the lv when md0 wasn't even active? The command lsmod shows
lvm-mod but not raid1. 

Here are some info which might be helpful:

[root@wspanic root]# mount
/dev/hda2 on / type ext3 (rw)
none on /proc type proc (rw)
none on /dev/pts type devpts (rw,gid=5,mode=620)
usbdevfs on /proc/bus/usb type usbdevfs (rw)
/dev/hda1 on /boot type ext3 (rw)
none on /dev/shm type tmpfs (rw)
/dev/hda7 on /usbstick type ext3 (rw)
/dev/vol01/logvol1 on /logvol type ext3 (rw)
//rhel3smb/public on /mnt/samba type smbfs (0)

[root@wspanic root]# dd if=/dev/zero of=/logvol/testfile bs=1M count=1
1+0 records in
1+0 records out

[root@wspanic root]# ls -l /logvol/testfile
-rw-r--r--    1 root     root      1048576 Nov 21 10:28 /logvol/testfile

[root@wspanic root]# cat /proc/mdstat
Personalities :
read_ahead not set
Event: 0
unused devices: <none>

[root@wspanic root]# raidstart /dev/md0

[root@wspanic root]# cat /proc/mdstat
Personalities : [raid1]
read_ahead 1024 sectors
Event: 1
md0 : active raid1 hda12[1] hda11[0]
      104320 blocks [2/2] [UU]

unused devices: <none>

[root@wspanic root]# ls -l /logvol/testfile
-rw-r--r--    1 root     root      1048576 Nov 21 10:28 /logvol/testfile
[root@wspanic root]# dd if=/dev/zero of=/logvol/testfile2 bs=1M count=1
1+0 records in
1+0 records out

[root@wspanic root]# ls -l /logvol/
total 2070
drwx------    2 root     root        12288 Nov 20 16:49 lost+found
-rw-r--r--    1 root     root      1048576 Nov 21 10:28 testfile
-rw-r--r--    1 root     root      1048576 Nov 21 10:29 testfile2

[root@wspanic root]# cat /etc/raidtab
# Sample raid-1 configuration
raiddev                 /dev/md0
raid-level              1
nr-raid-disks           2
nr-spare-disks          0
chunk-size              4

device                  /dev/hda11
raid-disk               0

device                  /dev/hda12
raid-disk               1

Version-Release number of selected component (if applicable):
lvm-1.0.8-5 / raidtools-1.00.3-7

How reproducible:
Always

Steps to Reproduce:
1. create /dev/md0 as RAID1 
2. pvcreate /dev/md0
3. create volume group with /dev/md0
4. create logical volume and make an ext3 fs on it
5. add entries in /etc/fstab for the lv
6. reboot machine

Actual Results:  logical volume is mounted, you can read/write to it
but /dev/md0 is not active.

Expected Results:  Both the logical volume and /dev/md0 should have
been activated. If not then the logical partition shouldn't have been
mounted. 

Additional info:

I created a new initrd file with the following options in
/etc/modules.conf:

alias md-personality-3 raid1
alias block-major-58 lvm-mod
alias char-major-109 lvm-mod

I tried building new initial ramdisks with just the raid1 module then
with only the lvm-mod and then with both. Got kernel panic in all cases.

I was able to work around the kernel panic by specifying the exact
partition 
of root instead of using labels like this:

   kernel /vmlinuz-xxxxx root=/dev/hda2 

It used to have something like this:

  kernel /vmlinuz-xxxxx root=LABEL=/

Somehow, the inclusion of the lvm-mod module must have lead to
something similar to bugzilla #109887 that is why the LABEL=/ was no
longer recognized. If I use the backup initrd file, I never have to
change root=LABEL=/.